It is well known that, although the possession of detailed local knowledge will usually be of great value towards the formation of plans of attack, there are occasions when local knowledge is apt to make local difficulties loom extremely large. For instance, in this particular case, the navigational difficulties caused by the strong tidal stream, the difficulty of recognising objects on the low-lying shore during darkness, the uninviting appearance of the outer Mole wall as an obstacle to be surmounted, and many other matters would probably have induced the belief, in those who were actually acquainted with these difficulties, that such attacks would have no chance of success. There is, therefore, reason to believe that, although they realised an attack might be attempted, the Germans were perfectly satisfied that the defences could neither be improved nor penetrated. The reader will probably have arrived at the conclusion that the Germans were devilish in their thoroughness. Yet there was still one joint left in their armour--and we penetrated it. But I must not anticipate. {35} CHAPTER III THE OUTLYING OBSTACLES. CONSIDERATIONS OF SALVAGE. Thus far I have only dealt with the local defences of Zeebrugge. But there were many other obstacles in our way--such as the coast batteries, mines, surface patrol vessels, submarines, aircraft, and the vagaries of the weather in addition to the navigational difficulties mentioned in the first chapter. The coast-line of Flanders bristled with guns. The section of the coast from three miles west of Ostende to six miles east of Zeebrugge, approximately twenty-one miles in length, was defended by two hundred and twenty-five guns; one hundred and thirty-six of these were of the heavy type, i.e., six-inch and above, up to fifteen-inch guns. At one period of the war, soon after the Germans first obtained possession of that locality, the coast defences had been few and far between. In those days our ships used to bombard from such short ranges as ten thousand yards. In course of time heavier guns were set up on shore so that our vessels were forced to keep at a more respectful distance. The first bombardments from ten thousand yards had been answered by the establishment of German guns having a range of fifteen thousand yards. When better weapons became available for bombardment from twenty thousand yards the Germans replied with guns {36} firing up to twenty-five thousand yards. And thus the duel continued. Finally, the ranges increased to upwards of forty thousand yards (twenty-three land miles). Monitors were specially constructed for this purpose and their marksmanship was wonderfully accurate. This accuracy is borne out by the fact that scarcely any damage was caused to the residential quarter, although Ostende was bombarded again and again; yet works of military importance, such as docks and railway stations, closely adjoining the residential quarter, were hit time after time.